US 2006/0130784 A1 · TWO-STROKE INTERNAL COMBUSTION ENGINE

Abstract

A crankcase scavenged two-stroke internal combustion engine (1) in which a piston ported air passage is arranged between an air inlet (2) and the upper part of a number of transfer ducts (3, 3′). The air inlet is equipped with a restriction valve (4), controlled by at least one engine parameter, for instance the carburetor throttle control. The air inlet extends via at least one connecting duct (6, 6′) to at least one connecting port (7, 7′) in the engine's cylinder wall (12). The connecting port (7, 7′) is arranged so that when the piston is in a top dead center configuration, it is connected with flow paths (9, 9′) embodied in the piston (13). The flow paths (9, 9′) extend to the upper part of a number of transfer ducts (3, 3′), and the flow paths in the piston are arranged so that the recess (10, 10′; 11, 11′) in the piston that meets the respective transfer duct's port (31, 31′) in a manner that the air supply is given an essentially equally long period, counted as crank angle or time, in relation to the fuel and air mixture inlet period.

Claims44

Dependent claims

A crankcase scavenged two-stroke internal combustion engine (1) having an inlet period in which a piston ported air passage is arranged between an air inlet (2) and the upper part of a number of transfer ducts (3, 3′), wherein the air passage is arranged from the air inlet (2) that is equipped with a restriction valve (4) which is controlled by at least one engine parameter, the air inlet extends via at least one connecting duct (6, 6′) to at least one connecting port (7, 7′;

8, 8′) in the cylinder wall (12) of the engine, which is arranged so that the at least one connecting port (7, 7′;
8, 8′), in connection with piston positions at the top dead center, is connected with flow paths (9, 9′;
10, 10′;
11, 11′) embodied in the piston (13), which extend to the upper part of a number of transfer ducts (3, 3′), and the flow paths in the piston are so arranged that recess (9, 9′;
10, 10′, 11, 11′) in the piston that meets respective transfer duct's port (31, 31′) is arranged so that the air supply is given an essentially equally long or longer period, counted as crank angle or time, in relation to the inlet period.

2 more elements

A crankcase scavenged two-stroke internal combustion engine comprising:

a piston reciprocatingly arranged within a cylinder;
a flow path configured to selectively place an air inlet duct in fluid communication with a scavenging duct;
said air inlet duct extending to an air inlet port formed in a cylinder wall of said engine and said scavenging duct extending from a scavenging port formed in said cylinder wall of said engine;
said air inlet port being positioned in said cylinder wall so that when said piston is positioned in a top dead center configuration, said air inlet duct is connected in fluid communication with said flow path;
and
said flow path being configured to extend from said air inlet duct to said scavenging duct when said piston is in said top dead center configuration so that a period of air supply through said air inlet duct to said engine is essentially as long as a period of fuel and air mixture supply to said engine during substantially each cycle of said two-stroke internal combustion engine, each of said periods being measurable based on at least one of crank angle and time.

3 more elements

Dependencies are inferred from the claim text.

Two-stroke internal combustion engine

Life of this patent

Two-stroke internal combustion engine

Life of this patent

Abstract

Claims44